Core drill



Feb. 8, 1938. w. OTTO ET AL CORE DRILL Filed April 8, 1956 3 mumoaao,Erancdslijcoii.

Patented Feb. 8, 1938 UNITED STATES PATENT OFFICE CORE DRILL ApplicationApril 8, 1936, Serial No. 73,222

3 Claims.

This invention relates to improvements in drilling apparatus, moreespecially in core drills, and its objects are as follow;

First, to provide a core drill to be used in drilling for oil, gas andwater, and which is of such a construction that it can be attended byone man.

Second, to provide a drill of the character described which when usedfor any of the foregoing purposes or for the drilling of test and shotholes in mining and tunnel work, is adapted to pumping out the corecuttings and removing the same to the surface of the ground so that thekind of earth formation through which the bit is passing can beinspected at any and all times without ceasing drilling operations.

Third, to provide a drilling apparatus which is made so light that itcan be moved in a small trailer by any ordinary kind of automobile.

Other objects and advantages will appear in the following specification,reference being had to the accompanying drawing in which Figure 1 is acentral vertical section of the bitcarrying body which functions as apump.

Figure 2 is a detail side elevation of the drill bit which screws on tothe bit body.

Figure 3 is an elevation of the framework of the drill rig, showing thedrill in position.

Attention is first directed to Figure 1 which illustrates the previouslymentioned bit body or so called pump. This body has chambers l, 2 and 3through which core cuttings pass. A transversely situated pin 4 limitsthe upward movement of a ball valve 5. This ball valve is 3 displaced tothe dotted line position 5 from its normally occupied seat 6 in order toallow core cuttings to pass on their way to the surface.

Holes, such as I, 8 and 9 (Fig. 1) and In (Fig. 3) are bored into thebit body so that they communicate with the chamber 2. These holes aresituated on sharp angles. They are directed upwardly toward the ballvalve 5 and thus facili tate the passage of the cuttings toward and pastthe ball valve.

The bit body, or pump as it has been called, is now designated ll. Atits upper end it has a standard left-hand pipe thread l2. At its lowerend it has a heavy left-hand thread I3 to match the correspondinglythreaded socket in a known type of drill bit M. This is known as an airhammer bit. It has cutting edges IS. A hole [6 beginning at theinternally threaded socket and going through the bit admits corecuttings from the bottom of the hole to the pump II to be pumped out tothe surface through the drill stem as will be understood.

Reference is now made to Figure 3. A rubber hose 25, of which only asmall portion is shown, disposes of the core cuttings. This hose isattached by means of a swivel joint 26 to a heavy 1 A" drill stem 21.This drill stem is made up of heavy pipe sections with screw joints onthe inside. This arrangement leaves the stem smooth on the outside.

A support 28 carries a screw 29. This screw is in the form of a. sleevethrough which the drill stem 21 passes, the function of the screw sleevebeing to regulate the working of the bit H on the bottom of the hole,this being accomplished by turning the handle 29 as cutting proceeds.

A heavy steel spring 30 imparts a quick and added force to the downstroke of the drill. This insures fast cutting. A clamp 3| on the drillstem 21 provides a rest for the bottom of the spring 30, the other endof the spring abutting the screw sleeve 29. A guide 32 of anyappropriate type guides the drill stem 21 in its reciprocation.

A lift is generally designated 33. The showing is to be considered asconventional. Actually the lift can be made in a number of ways in orderto raise the drill stem 21 anywhere from 3 to 6" as may be desired. Thislift will be timed to raise the drill stem about two hundred times perminute. It will take hold of the drill stem when the bit I4 is on thebottom of the hole, raising the drill stem and releasing it when thelift is completed. It is then that the spring 30 imparts a powerful downthrust.

What we claim is:-

1. A core drill comprising a hollow stem having a cutting bit attachedto the lower end thereof, lift means applied to the stem medially of itsends and so operable as to periodically lift the stem, a rig which hasmeans to guide the stem, a spring carried by the stem, said stem havingan abutment with which one end of the spring is in engagement to resistthe lifting effort of said lifting means, and a screw sleeve againstwhich the other end of the spring abuts, said sleeve slidably carryingthe stem, said rig having a support in which said sleeveis screwed foradjustment to vary the tension of the spring.

2. A core drill comprising a hollow drill stem, composed of pipesections having inside joints which provide the stem with a smoothexterior, a cutting bit and means connecting the cutting bit to thelower end of the stem, a rig which has guide means for the stem andwhich has a screw support, a spring coiled around the stem and havingone of its ends in engagement with a clamp on the;stem, an externallythreaded sleeve screwed throigh said screw support, slidably' carryingand guiding the stem in addition to said guide means, and being abuttedat one of its ends by the otheriiend of the spring, said stem beingadjustable in'the screw support to vary the tension of the spring, andmeans to periodically lift the stem against the tension oi the spring.

3. A core drill colnprising a. hollow stem, a hose and means by which toconnect said hose to the uppepend of the stem to carry away cuttings, acutting bit and means connecting said bit to the lower end of the stem,said means cemprising a body with openings to admit the cuttings and avalve to control the passage of;said cuttings into the stem, a springwhich exercises only a. downward pressure so as to drive the bit to itswork, a rig on which the stem is guided, a pair of abutment meansrespectively on the stem and on the rig with which the opposite ends ofthe spring; contact to force the cutting bit down as stated, and liftmeans operating on the stem medially of its ends to produce liftingmovements of the stem against the tension of the spring. 7 WILLIAMO'I'IG.

F. ELMljR sco'r'r.

